Abstract <p>Electrochemical synthesis of hydrogen peroxide was performed on an anthraquinone-modified carbon/polymer composite. The method for the chemical modification of the electrode was improved by using a water–acetonitrile medium, as well as acetone, for sorbent purification; the influence of the electrode potential and polarization time on the synthesis of hydrogen peroxide was revealed. In the process of oxygen electroreduction, hydrogen peroxide was accumulated by means of potentiostatic cathodic polarization of the gas diffusion electrode coated with an anthraquinone-modified thin film of the carbon/polymer composite. It was established that the introduction of anthraquinone leads to the maximum accumulation of hydrogen peroxide in the first polarization wave of cathodic oxygen reduction, reducing the overvoltage of hydrogen peroxide formation and increasing the current efficiency.</p>